2025 Alewife Report and meeting information

[Lotalota]

The 2025 Lake Ontario Spring Prey Fish and Alewife Assessment report was recently published: https://sealamprey.org/pubs/lake_committees/common_docs/Weidel_eta_2025_LkOntariospringpreyfishandAlewifereport.pdf

 

For those interested in hearing an overview of the results, NY Sea Grant is hosting an alewife meeting in Oswego on 9/23 (info below).

 

🐟 Lake Ontario Alewife Updates – Free Seminar

 

Join us for a 1-hour seminar on the current state of Alewife, a key forage fish supporting the Lake Ontario's prized trout and salmon fishery.

 

📅 September 23, 2025 |  6:30–7:30 PM

📍 SUNY Oswego | Shineman Hall Auditorium, Room 122

 

We’ll cover:

🔹 Causes behind spring Alewife die-offs

🔹 Latest findings from the lake-wide bottom trawl survey

🔹 Q&A and open discussion

 

Hosted by New York Sea Grant’s Great Lakes Fisheries Specialist, Stacy Furgal, with guest speaker Dr. Brian Weidel (USGS Tunison Lake Ontario Biological Station) and a welcome from Dr. Lisa Glidden (Director, SUNY Oswego Great Lakes Institute). See the event flyer here:  https://nyseagrant.info/loalewifeupdate0925

 

Parking info: Enter "Shineman Center, Centennial Dr, Oswego, NY 13126" into your GPS. Free parking is available in the lots closest Shineman Center.

[LongLine]

Lota - Thanx for posting.

 

Brian W. - Great report!  Thanx to you and crew for the hard work.

[Yankee Troller]

Would love to attend, but it's my sons B-Day.

 

I'm really curious to see next Springs trawl after the lake-wide die off this Spring/Summer. If it weren't for that die-off, I'd be very optimistic about the future and would be in favor of getting our stocking numbers back up to where they were before the mid teens cuts. Unfortunately, I don't think we know what the die-off did to the biomass?

[Lotalota]

10 minutes ago, Yankee Troller said:

Would love to attend, but it's my sons B-Day.

 

I'm really curious to see next Springs trawl after the lake-wide die off this Spring/Summer. If it weren't for that die-off, I'd be very optimistic about the future and would be in favor of getting our stocking numbers back up to where they were before the mid teens cuts. Unfortunately, I don't think we know what the die-off did to the biomass?

 
Haha guessing he doesn’t want to attend an alewife meeting as part of his party?

 

We’re going to make some video summaries to share for folks that can’t attend. I’ll start compiling questions from this thread and will share the responses post-meeting. 

[GAMBLER]

21 minutes ago, Yankee Troller said:

 

 

I'm really curious to see next Springs trawl after the lake-wide die off this Spring/Summer. If it weren't for that die-off, I'd be very optimistic about the future and would be in favor of getting our stocking numbers back up to where they were before the mid teens cuts. Unfortunately, I don't think we know what the die-off did to the biomass?

I feel that same way.  Seeing dead alewife all over the surface and all over the bottom (on camera) was a little concerning.  

[LongLine]

IMO:

The report estimates 17,400,000,000 alewives lakewide. Did some simple math and if correct then if 100,000,000 died off then only 0.57% died off.  If the typical alewife was 4" long x 1" high x 1/4" thick, then it would occupy 0.00058 cu ft. and 100,000,000 would occupy 57,870 cu ft. or enough to fill over 80 large dump trucks (if laid out flat). 

 

Another way to look at it is if the typical boat is 20 ft long x 8 ft wide, it occupies a "boat patch" of 160 sq ft.  The typical alewife occupies about 0.0278 sq ft. so 100,000,000 would fill a patch of 2,778,000 sq ft. (if floating side by side) or equivalent to approx. 17,300 boat patches.  

 

Another way of looking says that 100,000,000 4" fish laid end to end would stretch over 30 times the distance from Hamilton to Cape Vicent. 

 

Overall, 100,000,000 is a lot of fish, but a drop in the bucket compared to the estimated population.
 

TO me the issue isn't the quantity of alewife but the health of them. 

[Gill-T]

You need to go fishing 

[LongLine]

heh, heh, heh...probably true. 

 

So more alewife on CN side...is that why the CN fish are bigger than US fish?  Do US fish stray over there for more abundant prey?  More CN alewives because the bottom structure is so much different over there?  Is there a chemical difference in the water?  (Anecdotally, Toronto is a pretty good polluter.  MODIS generally shows green water along US shore but rare on CN side.)  More stable water on CN side?  I.E. not as serious upwellings? 

[yank my line]

Maybe there's larger fish that get to reproduce over on the Canadian side. Not like the Salmon River.

[Morgan-E]

Should be a great presentation - looking forward to seeing many of you there!

[HB2]

Al I know is I saw more bait down there than I have in a lot of years . Sometimes it was endless . So that should be a good thing 

 

[Lotalota]

For those that can’t make the meeting- any questions you want us to ask? 

[jk1]

Could you or they give a quick answer to what happened to the alewives in Keyuka.   We had tons of the until two years of  full thick ice coverage and then that flood with the dirty water lasting for weeks.   Not quite on the subject but if it could happen there could it happen in Lake Ontario.......jk

[LongLine]

On 8/19/2025 at 9:28 PM, LongLine said:

Do US fish stray over there for more abundant prey?  More CN alewives because the bottom structure is so much different over there?  Is there a chemical difference in the water?  (Anecdotally, Toronto is a pretty good polluter.  MODIS generally shows green water along US shore but rare on CN side.)  More stable water on CN side?  I.E. not as serious upwellings? 

 

Is there a chemical difference between waters on both shores?  Are there more quaggas on south shore?  Is there more plankton along the North shore?  More algae?  Does the North shore have the temperature swings that the south shore has?  Was there an alewife dieoff on the north shore like the south shore had?  was it as drastic?  Do east winds affect the North shore as much as they do on the South shore?

[Gill-T]

Probably a food web thing. Not sure there is plankton sampling going on during the winter months to confirm but if I had to guess there may be more of the mysis species concentrated on the bottom off the North shore. Pure conjecture. Maybe Dr Weidel can jump in here. 

[schreckstoff]

All interesting ideas, and great discussion. A  couple things to keep in mind about Alewife distribution during the April survey. The reason that trawling in Canada AND US waters is because the Alewife distribution appears to change year to year. Some years density is MUCH higher in US waters, some years the opposite, some years it is even.

 

Most Alewife are caught in trawls fished between 150 and 500 feet, whether in Canada or US.  Canada happens to have 65% of the lake area at those depths, and US has 35%, which means when Alewife are a little more dense in Canada the increased area of those depths makes the US / CA difference even bigger.

Maybe, just maybe, there is some evidence that in colder / longer winters the Alewife might be more in Canadian waters.  This could contribute to why for so many years US scientists focused so much emphasis/importance on cold winters as what 'kills' Alewife or reduces recruitment...if the fish were in Canada, and we only surveyed US waters....it looks like they weren't there when it was a survey bias.

Now that we sample both sides, and survival estimates make more sense, I can continue to have some bias in our estimates of Age-1 fish.  We openly discuss that in the reports. I'll keep working on it figuring out how to survey with less bias by continuing to listen to and incorporating the diverse ideas that you all share.  A Spoonpullers post about bias in the 2010 survey results, when US only survey results said Alewife numbers were down but Canadian fishers described more Alewife than they had ever seen is what originally tipped me off to do the analyses and eventually adjust the survey. 

 

[LongLine]

Brian, Thanx for the job you do.  Do you have any comparative information on the condition of age 1 alewife from the US side trawls vs the CN trawls?  The report shows the condition of 6.5" fish as a weight but that is for the overall lake.

 

 

[chinook35]

On 8/19/2025 at 11:44 AM, GAMBLER said:

I feel that same way.  Seeing dead alewife all over the surface and all over the bottom (on camera) was a little concerning.  

I can’t help but remember the die offs in the 50’s -60’s -70’s   Our camp on the lake side of Sandy Pond had “ mooneyes “ ankle deep in the beaches. We would rake them into piles and burn them 

That was before the introduction of the Pacific salmon 

Can this die off be an effect of salmon stocking being cut back ? 
I realize that the yearly die off is a natural occurrence, but it was almost non existent for many years after the salmon introduction